Furnace



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FURNACE MI. DUNCAN Filed March 14 the combustion zone on the grate.

limited area of the combustion none on the. ordinary traveling grate all of the combus antata i, niria 1 UNITED FURNACE Application filed lttarch ll, 1919. Ecrial N0. Emit/7M.

To all whom Wmg concern): i

lie it known that 1, WILLIAM li/lplD unoart, a citizen of the United States of America, a resident ofillton, in the county of Madison, Stateoflllinois, have invented 1 certain new and useful improvements in Furnaces; of which the followlng IS a full clear, and exact descrlption, reference being had to the accompanying drawings, forming a part of this specification.

ltfyinvention relates to improvements in furnaces and more particularly to furnace provided with a traveling grate.

Prior to this "invention endless chain grates have been used to carry fuel through thecombustion chambers of furnaceabut such grates have been constructedand ar' ranged to discharge the ashes at one endof @vvin to tible constituents of the fuel are not consumed in the furnace, some ofthe carbon and other valuable fuel elements being discharged With the ashes at a point aboutmich Way of the length of the furnace. Another important problem involved in the use of the ordinary travelingchain grate lies in the I difficulty of removing the ashes from the furnace. The most common practice is to form a deep ash plt under the nnddleportion of the furnace, Where the ashes are di a a charged from the grate, and to usemechani calrconveyers and blowers for the purpose oflifting the ashes and conveying them to the floor level at the front or rear of the furnace.

a @ne of the principalobjects of thisinvention is to increase the eiliciencyby provid ing a traveling grate on which substantially all of the ,fuel is consumed, and this is accomplished by retaining the fuel. in the combustion chamber in such a nanner that the elements which do not burn. readily are naturely discharged with the ashes. .A more important object is to entirely eliminate theexpenseof forming ash pits under the furnace, and to entirely eliminate the labor and expense of using special ash handling appliances for the purpose of ele vatingthe ashes to the floor level.

Briefly stated, both of the foregoing objects are attained by the useof a fuel can rier and ash conveyor comprising an elon= gated travelingchain grate which may extend from a fuel intake at one end of the furnace to an ashoutlet at the opposite end. rlbout tivo-thirds or one-half of the top surface of the elongated traveling grate lies in the combustion chamber, and this twothirds or one-half is preferably longer than the total length of an ordinary chain grate. This enables the fuel to be niost effectively consumed in the combustion chamber. The remaining one-third or one-half of the elon gated grate performs the function of an ash conveyor, and it enables the ashes to be delivered at a convenient point above the floor level Without using special ash handling ap pliances. lit will therefore be understood that the rate structure herein disclosed is he" something more thanan extra lon 'ratc. It

is a fuel carrier and ash conveyor; while the oi."dinar v chain grate is not an ash conveyor in. the sense that l use the term. The new grate structure actually conveys the ashes from the combustion zone to a distant discharge opening Where the ashes are discharged above the floor level and at the exterior of the furnace. In addition to savlng the labor and expense of excavating for ash pits and thereafter removing the ashes therefrom, the new structure can be most a furnace equipped with my combined fuel ignited and consumed, instead of being pre carrier and ash carrier. Fig. fl is a transverse section taken an proximately on the line ill--11, Fig. 1.

Fig. lllll is a transverse section on line Ill-Ill, Fig. l.

i IV is a detail View of the ash receivmately equal in length. A luel intake 4 is formed in the front wall, and an ash outlet 5 is formed in the rear wall.

A designates a fuel carrier and ash conveyor in the form of an endless elongated traveling chain grate passing through the intake 4: and outlet 5, said chain grate being mounted on wheels 6 and 7 at the exterior of the furnace. The Wheels 6 in front of the furnace may be idle wheels, and the wheels I at the of the furnace may be fixed to a power shaft 8 which may be rotated by any suitable mechanism. A coal hopper 9 is located in front of the fuel intake 4 to provide for the delivery of fuel to the grate.

The traveling grate is inclined upwardly from the fuel intake l to the ash outlet 5, so that the ashes will be discha ged at a relatively high elevation. A hooo. or housing 10 may be placed around the discharge end of the grate, so as to form an ash coinpartinent above the floor level.

B designates an elongated shield located in the rear portion of the furnace for the purpose of protecting the ash conveying portion of the grate from the i. nse heat in the combustion chamber. This shield B lies above and adjacent to the grate, as to provide a restricted ash passageway lead... from the combustion zone to the outlet 5. Smoke and gaseous products oi'f coinbustion are conducted downwardly at tie rear of the furnace, through a smoke passageway 12. The combustion zone for solid fuel on the grate extends from the fuel intake a to the shield l3 and this acne is extra long so maximum efliciency may be obtained by consuming all of the combustible material in the fuel. The combustible gases rising from the solid fuel are consumed at all points between the boiler and the combined fuel carrier and ash conveyor. It is therefore very hot in the combustion chamber above the ash conveying portion of the endless grate, and since the relatively thin bed. of ashes would not effectively protect this portion of the grate, I prefer to use the shield B to prevent injurious overheating or burning of the ash carrying )ortion of the apparatus. This shield comprises fireproof: blocks 18 supported on metal T-bars 14.1.

In the combustion zone for solid fuel, the grate is cooled by air currents passing through draft boxes l5, each of said draft boxes being open at one end to receive a. :lorced draft and open at the top to deliver the air currents through the fuel supporting portion of the grate.

An ash-catching table C, formed by a number of metal plates or sheets 16, is arranged below but adjacent to the bottom face of the ash conveying portion of the grate. A very narrow ash passageway is thus formed from the rearmost draft box 15 to the ash outlet 5. The grate itself will serve as a sweep for moving the ashes along the ash-catching table C. This table also prevents the admission of air from the open lower portion or the furnace to the ash con-- reying portion of the grate.

1T designates a U-shaped ash-receiving pocket located at the rear of the furnace, beyond the ash outlet 5, and forming a con-- tinuricion of the ash-catching table C. The

and table C are surrounded by c s grate, and the pocket is open at the top to receive the ashes discharged at rear end oil table C. This pocket is :lso open at its ends to permit the ashes to drop into the ash compartment 10 without striking the lower portion of the endless grate structure.

The upper portions of the elongated chain support a long bed of fuel and a long bed of ashes. Since these upper portions driven for a considerable distance While l to the .veight of the fuel and ashes, ably utilize tracks and rollers to t the same. The chain grate consists ll endless chains formed by endless rows of grate links connected by pivot rods 18, and anti-friction rollers 19 are rotata .ly mounted on these pivot rods at points between adjacent grate links. Tracks 20, surrounded by the endless grate, extendfrom the fuel intake 4; to the ash outlet 5, said tracks being located below but adjacent to the upper course of the traveling grate.

i ne rollers 19 extend slightly below the upper grate links and they travel on the tracks 20. in the combustion zone, above the draft ll .15, the bottom faces of the grate bars l e or lie very close to transverse sepg bars; between the d aft bars, by preventing rec escape of the draft from. one box to the zone over another draft box. At the rear portion of the furnace, innnediately below the ash-conveyin portion ol? the grate, the tracks 20 lie be tween and form supports for the ash-cati-h plates 16, as in Fig. II.

it the lower portion of the long endless structiu'e. the grate links are inverted, with their fuel-receiving faces exposed at he bottom of the structure, and continuous "riction tracks 21 are arranged below said lower portion and engaged by said fuel-receiving surfaces to form long friction slides on which the lower grate links are supported. Prior to this invention, it has been customary to cause the lower returning portion of the grate to travel over transverse rollers as it moves toward the fuel intake. the rollers being mounted at fixed points below the grate structure. In actual practice I have found that a link will occasionally break and hang from its pivot rods. with the result of striking the rollers below the grate, thereby causing serious injury to nataaai the traveling grate structure. However, in accordance with the present invention, if the long tracks 21 are used with unobstructed spaces between them, a broken link would travel freely over i a continuous track or hang freely in an unobstructed space between two tracks, untll it eventually reaches one end of the structure, where it can be readlly observed and repaired by the operato-r.

I claim:

1. A furnace having a fuel intake, an ash outlet and a combustion chamber between said intake and outlet, a fuel carrier combustion chamber to convey the ashes to i said outlet, a shield arranged over the ash conveying portion ofthe grate to protect said portion from the heat of the combustion chamber and an ash-catching plate arranged immediately below said ash conveying portion of the grate, said shield and ash-catching plate being extendedfrom the combustion chamber to said ash outlet.

2. A furnacehaving a fuel intake, an ash outlet and a combustion chamber. between said intake and outlet, a fuel carrier and ash conveyor comprising an elongated travcling grate having a fuel supporting portion in the combustion chamber and an ash conveying portion extending from said combustion chamber to convey the ashes to said outlet, an ash catcher arranged below said ash conveying portion, said ash catcher being immediately adjacent to the bottom face of the traveling grate to provide a narrow ash passageway below and longitudinally of the grate, so that the grate will serve as a sweep for moving the ashes along said ash catcher and toward said outlet, and an ash-receiving pocket arranged to receive ashes from said ash passageway.

3. A furnace having a fuel intake, an ash outlet and a combustion chamber between said intake and outlet, a fuel carrier and ash conveyor comprising an'elongated travveying portion extending from said combustion chamber to convey the ashes to said outlet, an ash catcher arranged below said ash conveying portion, said ash catcher being immediately adjacent to the bottom face of the traveling grate to provide a narrow ash passageway below the grate, so that the grate will serve as a sweep for moving the ashes along said ash passageway and toward said outlet, and an Mash-receiving pocket arranged to receive ashes from said ash passageway, said ash-receiving pocket being open at the top to receive the ashes discharged from said ash passageway and said pocket being open at one side of the grate to discharge the ashes.

a. A furnace having a fuel intake, an ash outlet and a combustion chamber bet-ween said intake and outlet, a fuel carrier and ash conveyor comprising an elongated travcling grate having a fuel supporting portion in the combustion chamber and an ash conveying portion extending from said combustion chamber to convey the ashes to said outlet, a shield arranged over the ash conveying portion of the grate to protect said portion from the heat of the combustion chamber, and an ash-catching plate arranged immediately below and separated from said ash conveying portion of the grate to provide an ash passagewaybelow said shield and ash conveying portion.

5. it furnace having a fuel intake in its front wall, an ash outlet formed transversely of its rear wall, and a combustion chamber adjacent to said fuel intake, a fuel carrier and ash conveyor comprising an elongated traveling grate extending from said fuel intake to said ash outlet,and a shield arranged over said elongated traveling grate and extending from said combustion cham- I berto the ash outlet in said rear wall, said elongated traveling grate having a fuel supporting portion in said combustion chamber and an ash conveying portion located below said shield and extending from said combustion chamber and entirely through the ash outlet in the rear wall.

In testimony that I claim the l hereunto affix my signature.

"WILLIAM M. DUNCAN.

foregoing 

